Generally, a method in which an aliphatic carboxylic acid or its derivative is reacted with ammonia is known industrially as a method of producing an aliphatic nitrile. This method is roughly classified by reaction form into a gas phase method and a liquid phase method. JP-A 4-208260 discloses, as the vapor phase method, a method in which an aliphatic carboxylic acid or its derivative which has been vaporized in advance is reacted catalytically with ammonia at a temperature of 250 to 600° C. by using, as a catalyst, an oxide of Zr, Ta, Ga, In, Sc, Nb, Hf, Fe, Zn or Sn. JP-A10-195035 discloses a method in which an aliphatic carboxylic acid or its alkyl ester which has been vaporized in advance is reacted catalytically with ammonia at a temperature of 200 to 400° C. by using zirconium oxide poisoned by a metal polyvalent cation.
In the case of reacting in the liquid phase method, on the other hand, an aliphatic carboxylic acid or its derivative is dissolved under heating in the presence of a catalyst and ammonia gas is blown into the solution to react both in a batch system or in a continuous system. For example, JP-A 58-39653 discloses a method in which iron or an iron compound is used to react at 150 to 290° C.
JP-A 2000-80069 discloses a production method using a complex oxide which is sparingly soluble in a reaction solution and obtained by compounding an oxide of one or more elements selected from the group consisting of silicone, niobium, zirconium, tantalum, gallium and gelmanium with titanium oxide at a reaction temperature of 300° C. or less.
U.S. Pat. No. 6,080,891 and U.S. Pat. No. 6,005,134 disclose methods in which an aliphatic carboxylic acid, aliphatic carboxylic acid lower alkyl ester or aliphatic glyceride is reacted with ammonia by using an oxide catalyst obtained by using titanium oxide as its major component and by compounding an oxide of one or more elements selected from the group consisting of niobium, zirconium, tantalum, gallium and germanium, and also, a method of producing an amine by hydrogenating the aliphatic nitrile. A metal alkoxide is used as a titanium source.